Laser Therapy: Hope or Hype and Hokum?

BY HARRIET HALL, M.D.

I love to watch TV reality shows about veterinarians. There are quite a few of them now. My favorite is “The Incredible Dr. Pol.” I learn a lot from them, for example that “polio” in goats means a vitamin deficiency disease, not the infectious disease that humans get. And I have learned that dogs don’t have blood types, so any dog can donate blood to any other dog. That’s good to know, but as a skeptic there are a few things on those shows that I question. I have frequently seen TV veterinarians use laser therapy to speed wound healing from both injuries and surgical incisions. I kept wondering “Is that for real? Is it based on science or superstition?” I decided to look into the evidence.

What are Lasers?

“Laser” stands for “Light Amplification by Stimulated Emission of Radiation.” Einstein established the theoretical foundation in a 1917 paper, and the first laser was built in 1960. Lasers emit coherent light that can be tightly focused and has a limited spectrum, emitting a single color of light. Output can be continuous or pulsed. A laser that produces light is technically an oscillator rather than an amplifier, and it has been suggested that the acronym LOSER—Light Oscillation by Stimulated Emission of Radiation— might have been a more correct acronym, although it is apparent why that didn’t catch on! Today, lasers are everywhere and have many applications, from bar codes to laser printers, from surgery to welding, from entertainment to law enforcement, from DVD players to laser pointers (great for giving lectures and for playing with cats). There are many types of lasers; they can use visible light or other electromagnetic frequencies, from infrared to X-rays and even gamma rays.